Vacuum device



1931. A. w. FRANKLIN 1,814,681

' VACUUM DEVICE Filed June 11, 1927 3 h 5 attozmew Patented Jay 14, 1931 r OFFICE- ALBERT W. FRANKLIN, OF NEW YORK, N. Y.

VAGUUIvI DEVICE Application filed June 11,

This invention relates in general to vacuum devices of the type for instance, known as the audion. V a I One of the objects of this invention is the provision of an electron discharge device, so interconnected as to materially reduce the electro magnetic and the electrostatic field, produced by the current and the voltage applied to the cathode.

A further object of this invention is the provision of heating means for the cathode or electron emitter which is arranged so that the current through any portion of the heater is'materially less than the current applied 5 to the terminals of the heater.

A still further object of this invention is the provision of a cathode and heater, therefor, in devices of this type adapted to be energized by alternating'current, without the 5 production of undesirable noises, due to the use of alternating current.

One of the prime objects of this invention is the provision of a heater or electron emitter or the combination of both, so connected to current terminals that the current in any portion ofthe heater or emitter is substantially equal to one-half of the current from the source and flows in opposite directions in various portions of the heater or emitter.

These and other objects as will appear hereinafter are sought by means of this invention.

This invention resides substantially in the construction, combination, arrangement and relative location of parts as will be more fully set forth.

Referring to the drawings, Figure 1 is a diagrammatical illustration of a cathode and heater employing the principles of this invention.

Figure 2 is a slightly modified form of this invention, and

Figure 3 represents an electron discharge device partly in vertical cross section employing acathode and heater of the form of this invention.

Many attempts have been made to provide vacuum devices of the electron discharge type, particularly when they are to be used in radio apparatus which can be used in concurrent.

1927. Serial No. 198,053.

nection with an alternating current source without the production of undesirable noises such as the hum produced by the alternating In the construction employed in this in-' vention a cathode and a heater therefor are duced by the varying electrostatic field resulting from the varying voltage of the alter nating current. The variations of the alternating current produces a variation in the heat produced resulting in an undesirable hum when the heater is of a small cross section, so that its temperature may to some extent at least, i follow the variations in the current.

By means of this invention the heater which has two portions connected in parallel operates at a potential diiference of one-half of that which would be required if the heator portions were in series and the current through any portion of the heater is approximately one-half that supplied from the source. The heater and cathode are inter connected so that the currents flowing Referring to the drawings at 1 and 2 are shown the current terminals to'which any suitable source of current may be connected. At 4e is shown a wire connected to the 0pposite ends of a heater shown as a filament for purposes of illustrations, comprising the portions 5 and 6. The emitter or cathode is shown at 7 in the form of a cylinder for purposes of illustration and has its opposite ends connected together by a wire 9. The wires 4: and 9 are connected at their approximate centers to the terminals 1 and 2 by means of wires 3 and 10 respectively. The heater is divided into its portions 5 and 6 by means of an electric connection at its approximate center to the approximate center of the emitter 7. By means of this arrangement, a current when applied to the currents 1 and 2 will travel as clearly shown by means of the arrows so that the current in each portion of the heater 5 and 6 is approximately equal to each other and to one-half the current in the leads 3 and 10. These currents flow in opposite directions. Similarly, the current flowing through the cathode 7 flows in opposite directions and the current in any section of the cathode is equal to one-half of that in the wires 3 and 10. The electrode or electron emitter may if desired, be coated with any suitable electronically active oxide, as is well known in the art.

The arrangement of Figure 2 is substantially the same as that in Figure 1 except that the wire 9 has been eliminated and the wire lO co'nnected to the approximate center of the cathode 7. It has been found in practice that the arrangement of Figure 2 gives substantially the same result as that in Figure 1.

The arrangement of Figure 2 is shown in combination with other elements in a completed device, as illustrated in Figure 3. The cathode 7 is surrounded by the grid 1.5 which has a wire connecting it to one of the terminals 13 mounted on the base 12. All the elements are enclosed within an evacuated vessel having the usual internal projecting stem tube 14. Surrounding the heater, cathode and grid is a plate 16' which is likewise connected by a wire to one of the terminals 13. The upper end of the heater is supported by means of wires secured to the wires 4: and 9 and held together in separated position by the glass bead 17.

, It is of course, intended that the disclosure in Figure 3 is for the purpose of illustrating the principles of this invention without attempting to illustrate a practical embodiment thereof, that is, practical with respect to the means for mounting the various elements and maintaining them in proper relation. Such means are of course, well known in the art. The operation of the de vice in Figure 3 with respect to the cathode and heater has been given in this disclosure in Figures 1 and 2 and need not be repeated ere.

It is evident that I have devised a new and novel method of connecting the cathode of an electron discharge device, which, as will be apparent to those skilled in the art,

is capable of many modifications and changes in the detail of construction and relative arrangement and connection of the parts.

Although Figures 1, 2 and 3 disclose a heater filament with an emitter or cathode surrounding said filament, it is apparent that the filament may be in itself the cathode or emitter.

I do not therefore desire to be strictly limited to the disclosure in the drawings which has been given for purposes of illustration but rather to the scope of my invention as itis defined in the appended claims.

For instance, it is evident that the shape and relative arrangement of the elements of the vacuum device can easily be changed without departing from the spirit of this invention.

Therefore, what I seek to secure by United States Letters Patent is:

1. The combination in a vacuum device of an electron emitter, means for heating said emitter and terminals for said heater, said emitter being connected at its ends to one terminal, said heater being connected at both ends to the other terminal and said heater and emitter being connected together centrally.

2. In a vacuum device the combination with a plurality of electrodes at least one of which is an electron emitter of a heater for said emitter and terminals for said heater, one of said terminals being connected to each end of the heater and the other to each end of the emitter and a connection between the,

heater and emitter to divide the heater into two approximately equal parallel paths.

In testimony whereof I have hereunto set my hand on this second day of June, A. D.,

ALBERT W. FRANKLIN. 

